Lamp unit



Oct. 10, 1939. M. REGER ET AL 2,175,361

LAMP UNIT Filed Oct. 25, 1937 Fig, 2

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C 3 j 6 \j f A 7 if; f 8 k I -/4 2/ 23 n :1 A5 I i,/ I ,6 v l9 8 23 /7 24 INVENTORS Martin Regen" Willy Frji't BY Wan/'7 107E141 ATTORN EY Patented Oct. 10, 1939 PATENT OFFICE LAMP UNIT Martin Reger, Berlin-Charlottenburg, and Willy Freitag, Berlin-Treptow, Germany, assignors to General Electric New York Company, a corporation of Application October 25, 1937, :Serial No. 170,960 In Germany October 28, 1936 2 Claims.

The present invention relates to lamp units generally and more particularly the invention relates to lamp units of the type comprising a gaseous electric discharge vapor lamp device and a heat conservator enclosing said discharge lamp device.

The object of the invention is to provide a lamp unit of this type which is simple in structure and which is manufactured inexpensively. Still fur- 10 ther objects and advantages attaching tothe device and to its use and operation will be apparent to' those skilled in the art from the following particular description.

Lamp units of this typeare now available in 16 commerce and in one type thereof the heat conservator is a sealed'envelope of vitreous material which is provided with a flared stem of vitreous material having a pinch into which the current leads for the lamp device are fused. The

20 present invention attains its objects by utilizing a' closure plate consisting of ceramic material in' place of the flared stem of vitreous material now used. The closure plate is fused to the heat con- ,fI SGIVEtOI and hermetically closes the open end 2 thereof. The current leads for the lamp device mounted in the heat conservator pass through the closure plate and are attached to contacts on the usual screwbasei or pin base fastened to said plate. W'e haveidemonstrated that the use of a o closure plate of ceramic material increases the mechanical'stren'gth of the lamp unit and facilitates the assembling of such units. In the manufacture of the lamp; unitthe closure plate and the lamp device are Joined by inserting the ourrent leads-of. the lamp device into passages in the closure plate, and the space between the leads and the plate is filled with a suitablsealing glass to hermetically close these passages. The lamp device is then inserted in the heat conser- 40 vator which consists of a vitreous vessel having an open end; 'Tlie closure plate is inserted in the openend of said conservator and is fused thereto .by interposing between the plate and the conservator a suitable sealing glass which seals the joint 45 between the plate and the heat conservator. The heat conservator is then evacuated through a passage in the closure plate and is then sealed off from the exhaust system in the usual manner.

A base, such as a screw base or a pin base, is then 50 attached to the closure plate. The closure plate consists of a ceramic material highly resistant to elevated temperatures and serves as a mold or mandrel to prevent any deformation of the vitreous heat conservator during the fabrication of the hermetic fused joint between said plate and said conservatorr The smooth symmetrical surface of the heat conservator is thus retained and the lamp unit has an improved appearance.

In the drawing accompanying and forming part of this specification two embodiments of the invention are shown in which:

Fig. 1 is a front, elevational, partly sectional view of one embodiment of the invention, and

Fig. 2 is a fragmentary, elevational, partly sectional view of another embodiment of the invention.

Referring to the drawing the lamp unit comprises a. gaseous electric discharge lamp device having an elongated tubular container I of vitreous material. Thermionic, activated electrodes 2 and 3 of the type heated to a high electron emitting, arc discharge supporting temperature by the discharge incident thereat are sealed into said container l-at each end thereof. Said electrodes 2 and 3 are mounted on and supported by current leads 4 and 5, respectively, which are fused into the projecting parts 6 and I, respectively, of said container I. Said container I has a gaseous atmosphere therein, comprising a starting gas, such as argon, at a pressure of about 1 to mm. and a quantity of vaporizable material therein,

7 such as mercury. When desired the quantity of xmercury is such that it is completely vaporized at the operating temperature of the container I. The lamp device is mounted in a vitreous heat conservator 20 which is rounded at one end and which has a ceramic closure plate 8 inserted in and hermetically closing the other end thereof. Said closure plate 8 consists of a ceramic material, such as a mixture of approximately 50% titanium oxideand approximately 50% magnesium oxide. The closure plate 8 has a shoulder I9 which rests against the end of the heat conservator 20. The space between the inner wall of the conservator 20 and. the closure plate 8 is sealed by a sealing glass which is fused to both of these elements to make an hermetic joint therebetween.

The discharge lamp device is supported in the heat conservator 20 by the current leads II and I2 which are inserted in the openings 9 and II], respectively, of the closure plate 8. Said current leads II and I2 are fastened to the protruding parts 6 and I, respectively, of the lamp device and are connected to the current leads 4 and 5 by suitable leads I3 and I4, respectively. Said current leads I I and I2 are connected to the leads I! and I8, respectively, which pass through holes I5 and IS in the plate 8, respectively, and which are fastened to the contacts on the screw base 24 which is fastened to the closure plate 8. The spaces between the closure plate 8 and the leads I! and [8, respectively, are hermetically closed by a sealing glass. An exhaust tube 23 is fused to said plate and communicates with a passage in said plate 8. Said conservator 20 is evacuated through said tube 23 during the manufacture of the lamp unit. After evacuation is completed said tube 23 is fused off from the exhaust system hermetically closing said heat conservator 20. When desired, an inert gas is introduced into the heat conservator after evacuation and before the conservator is sealed off from the exhaust system.

The device described above is a compact one of simple structure and is inexpensively manufactured.

The embodiment of the invention shown in Fig. 2 is similar in all respects to that shown in Fig. 1 with the exception that the heat conservator 20 consists of a double walled flask, known in the art as a Dewar flask, and the closure-plate 8 hermetically closes the open end of the flask. In this embodiment the space between the walls of the glass 25 as well as the space about the lamp device is evacuated and the closure plate 8 is provided with two contact pins 25 and 26 to which the current leads I1 and I8 are fastened, respectively. Said contact pins are inserted into recesses in the plate 8.

While we have shown and described and have pointed out in the annexed claims certain novel features of the invention, it will be understood that various omissions, substitutions and changes in the forms and details of the device illustrated and in. its use and operation may be made by those skilled in the art without departing from the broad spirit and scope of the invention, for example, additional support means, such as resilient springs which press against and are interposed between the lamp device and the heat conservator, are provided, when desired.

What we claim as new and desire to secure by Letters Patent of the United States, is:

1. An electric lamp comprising in combination, a heat conservator, a gaseous electric discharge lamp device mounted therein, said heat conservator being a vitreous vessel open at one end, and a closure plate consisting of approximately titanium oxide and 50% magnesium oxide and having a higher softening temperature than the material of said vessel fused to the open end portion of said vessel and hermetically closing the open end thereof, said closure plate extending into said vessel to prevent deformation of said vessel during the manufacture of said lamp.

2. An electric lamp comprising in combination, a heat conservator, a gaseous electric discharge lamp device mounted therein, said; heat conservator being a vitreous, double-walled vessel open at one end, and a closure plate consisting of approximately 50% titanium oxide and 50% magnesium oxide and having a higher softening temperature than the material of said vessel fused to the open end portion of said vessel and hermetically closing the open end thereof, said closure plate extending into said vessel to prevent deformation of said vessel during the manufacture of said lamp.

MARTIN REGER. WilLLY FREITAG. 

